Metrology of deep trench structures with polarized FTIR reflectance spectrum

Deep trench structures have been widely introduced to the IC and MEMS devices, such as bottle trench structures with an aspect-ratio of more than 50:1 has been adopted to form the capacitors on DRAM. The fabrication of this kind of structures challenges the traditional surface profile and shallow trench measurement technology. A polarized Fourier-transform infrared (FTIR) reflectance spectrometry has been developed for accurate measurement of deep trench structures with unsymmetrical cross section. As different from traditional FTIR reflectance spectrometry, this method introduces a polarized modeling method for deep trench structures with unsymmetrical cross section. The validity and accuracy of this method are investigated by the simulations of metrology of 1-D deep trench structures with different polarized radiations.